[Tommy]

The most likely scenario I can imagine where you might overwhelm the ammeter and/or wires would be by adding some high amp accessory. Or you might jump start the car with a nearly dead battery and then turn on every electrical accessory while you drive the car to recharge the battery. In all other high demand scenarios (e.g., a dead short in the fan wiring), a fuse should blow before the wiring overheats. Multiple simultaneous failures are theoretically possible, but unlikely. . . . Some cars have a inline fusable link for such events. As I designed the entire electrical system for my Cheetah, I included an 80 amp fuse between the alternator/battery and the main bus, and I used a voltmeter instead of an ammeter.